Most of the time, positional battles become more and more distinct as the season progresses. Usually, one talent emerges over the rest, one guy gets most of the playing time, or the starter gets hurt leaving the backup as the only usable option. However, there always remain a few divergent cases where even four weeks into the season, the most valuable fantasy player at a given position is still ambiguous. Today, we’re going to focus on three running back battles that still have the potential to change the rest of the way.

Bufallo Bills: C.J. Spiller vs Fred Jackson

Coming into the season, expectations were sky high for C.J. Spiller. He went as high as number two overall in drafts, and never slipped out of the first round. Through four weeks, we all look like fools for valuing him that highly. Spiller’s YPC has been cut nearly in half from 6.0 to 3.5, and he has just one reception in the past two weeks combined. Meanwhile, Fred Jackson has been fantastic in his supporting role with four times as many receiving yards and a YPC over 5.

The Bills offense as a whole has definitely improved since last season with EJ Manuel at the helm. They run at a pretty fast pace, and actually have the most rushing attempts in the NFL so far (as well as the 2nd most yards). A lot of the blame has been deflected because of Fred Jackson, but Spiller is actually getting 18.8 touches per game as opposed to 16.3 last season. He has the talent to capitalize, but with a small ankle injury and a Thursday matchup it may take even longer for him to get going. I still have faith in his talent after his incredible 2012, and value him as a top 10-15 RB the rest of the way. Jackson will also be effective and fits right around #30 for me.

Most thought the Patriots backfield would get some clarity this season, particularly when Shane Vereen went down with an injury. However, Stevan Ridley has not run away with the job by any means. Ridley has yet to score a touchdown this season, while also failing to top 11 carries or 60 yards rushing. Fantasy zombie LeGarrette Blount has worked his way into some meaningful time and while he has not looked consistently good, he has broken off enough good runs to continue to get touches. In the long-term, Ridley is the guy I want here, but he’s far from the potential top-10 back many drafted him as this season. Ridley ranks as low-end RB2 right now with some upside because I would never be comfortable starting LeGarrette Blount or Brandon Bolden. As Vereen’s approach nears (he’s eligible to return week 11), he should be stashed in almost all leagues as there is a chance he can work his way into the primary halfback for the Pats due to his ability to be a successful runner and active in the passing game.

Cincinatti Bengals: BenJarvus Green-Ellis vs Giovani Bernard

The Bengals two running backs compose one of the most interesting juxtapositions in the NFL. On the one hand, Giovani Bernard is absolutely loaded with upside and versatility—he looks great in the passing game, runs hard and fast, and has been very efficient so far this year. On the other hand, there are few running backs in football who are as consistent as BenJarvus Green-Ellis, and even though his efficiency this year is down, he’s still getting the majority of the goal line work and is also a much superior pass-blocker than Bernard. Out of the two, Bernard is the guy you want to own on this team thanks to his much superior upside, but it seems like both are going to have legitimate value this year. So far, the Law Firm has nearly doubled the carries of Giovani Bernard, but if Bernard continues to outperform Green-Ellis, the disparity in those carries should progressively become less and less as the season wears on. In deeper formats BGE is still a solid flex play, but in any format Bernard is an exciting guy to own—I just might wait until he gets work more consistently before starting him in shallower formats.